1. Field of the Invention
This invention relates to an electric stapler attached to a copier machine and the like.
2. Description of the Related Art
An electric stapler relating to the present invention is equipped with a table on which a set of copied sheets are placed, and a cartridge which holds sheet staples and is also provided with a magazine vertically movable to the table, a drive mechanism to move up and down the magazine and a driver plate to drive down a staple into the set of sheets from a staple supply portion.
The drive mechanism is provided with a drive motor, a series of speed reduction gears rotated by the drive motor, and a cam turned by the speed reduction gears. One turn of the cam makes one vertical reciprocating movement of the magazine, and the driver plate tied to the reciprocating movement of the magazine shoots staples from a staple supply portion. And a series of binding processes is completed with clinching flat legs of the staple which have pierced the set of sheets with a clincher mechanism provided on the table.
In this sort of an electric stapler, in order to drive down the staple into a set of sheets with reliability, the staples are driven down after the magazine descends from its home position and holds the set of sheets between the magazine and the table.
Incidentally, this type of conventional drive motor is driven for a designated period of time to make the cam one turn as shown with an alternate long and short dash line in FIG. 4. The angular velocity of the drive shaft of the drive motor increases with the passage of time until a certain lapse of time and the angular velocity W1 is accelerated to a high velocity when the magazine descends to the position where it holds the set of sheets with the table between.
Therefore when the magazine makes forcible contact with the set of sheets S, a strong force is applied on the table through the set of sheets S, which brings such a state as if the magazine crashed against the table. It has a disadvantage that the magazine has a heavy weight due to the installed cartridge which holds the sheet staples, giving a big impact on the table with a loud noise. And there is a possibility that the sheet staples may be separated at connecting portions. Particularly, in an electric stapler in which the table and the magazine are separated, these disadvantages are remarkable because the reciprocating motion of the magazine is set in high speed so that a series of binding processes can be completed in a short time.
In considering the above described disadvantages, it is an object of the present invention to present an electric stapler which can complete a series of binding processes in a short time with a reduced impact from the magazine.